Gout and 'pseudogout'. When are arthritic symptoms caused by crystal deposition?

The proper diagnosis of gout and pseudogout (ie, calcium pyrophosphate dihydrate crystal deposition disease) leads to correct treatment. The two disorders can be easily confused and misdiagnosed in certain situations. Thus, in every case, synovial fluid aspiration and microscopic synovial fluid analysis under compensated polarized light should be done to confirm the suspicion of crystal-induced arthropathy. Underlying diseases should always be sought, because many are treatable.